U.S. patent number 11,014,453 [Application Number 16/643,652] was granted by the patent office on 2021-05-25 for method for testing whether a current collector is in contact, and current collector.
This patent grant is currently assigned to Siemens Mobility GmbH. The grantee listed for this patent is SIEMENS MOBILITY GMBH. Invention is credited to Florian Buehs, Thomas Stark.
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United States Patent |
11,014,453 |
Stark , et al. |
May 25, 2021 |
Method for testing whether a current collector is in contact, and
current collector
Abstract
A method for testing whether a current collector of a vehicle,
which is preferably not rail-bound and is driven by an electric
motor, is in contact with a contact wire of an overhead line which
extends in a direction of travel. The current collector, which can
be moved along a vertical direction, has a carrier element and a
contact strip, resiliently mounted on the carrier element by a
primary spring element. The contact strip, upon contacting the
contact wire, is deflected relative to the carrier element counter
to the vertical direction out of a resting position, wherein the
deflection is detected by a sensor unit and it is determined
whether the contact strip is in contact with the contact wire.
There is also described a corresponding current collector.
Inventors: |
Stark; Thomas (Woltersdorf,
DE), Buehs; Florian (Berlin, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
SIEMENS MOBILITY GMBH |
Munich |
N/A |
DE |
|
|
Assignee: |
Siemens Mobility GmbH (Munich,
DE)
|
Family
ID: |
1000005573437 |
Appl.
No.: |
16/643,652 |
Filed: |
August 23, 2018 |
PCT
Filed: |
August 23, 2018 |
PCT No.: |
PCT/EP2018/072706 |
371(c)(1),(2),(4) Date: |
March 02, 2020 |
PCT
Pub. No.: |
WO2019/042848 |
PCT
Pub. Date: |
March 07, 2019 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20200238833 A1 |
Jul 30, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
Sep 1, 2017 [DE] |
|
|
102017215340 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
5/30 (20130101); G01D 5/14 (20130101); B60L
3/12 (20130101); G01R 31/006 (20130101) |
Current International
Class: |
G01R
31/00 (20060101); B60L 5/30 (20060101); B60L
3/12 (20060101); G01D 5/14 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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19529070 |
|
Feb 1997 |
|
DE |
|
102009009281 |
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Apr 2010 |
|
DE |
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102009036963 |
|
Feb 2011 |
|
DE |
|
102011076620 |
|
Nov 2012 |
|
DE |
|
102013201534 |
|
Jul 2014 |
|
DE |
|
2001235310 |
|
Aug 2001 |
|
JP |
|
2002328063 |
|
Nov 2002 |
|
JP |
|
164137 |
|
Aug 2016 |
|
RU |
|
Primary Examiner: Fortich; Alvaro E
Attorney, Agent or Firm: Greenberg; Laurence Werner Stemer
Locher; Ralph
Claims
The invention claimed is:
1. A method for testing whether a current collector of a vehicle is
in contact with a contact wire of an overhead line extending in a
direction of travel, wherein the current collector is movable in,
and counter to, a vertical direction, the method comprising:
providing the current collector with a carrier element and a
contact strip for contacting the contact wire resiliently mounted
on the carrier element by way of at least one primary spring
element, and providing the current collector with a sensor unit;
wherein, upon contacting the contact wire, the contact strip is
subject to a deflection out of a rest position counter to the
vertical direction relative to the carrier element; detecting the
deflection with the sensor unit of the current collector and,
dependent upon the deflection, determining whether the contact
strip is in contact with the contact wire.
2. The method according to claim 1, wherein the sensor unit
comprises a magnet element and a magnetic sensor element which are
displaceable relative to one another during the deflection.
3. The method according to claim 1, which comprises detecting a
deflection of the primary spring element in or counter to the
vertical direction.
4. The method according to claim 1, which comprises detecting an
inclination of the contact strip relative to the carrier element
about an inclination axis extending in the direction of travel.
5. The method according to claim 1, wherein the at least one
primary spring element is one of two primary spring elements, and
the contact strip is resiliently mounted on the carrier element by
the two primary spring elements spaced apart from one another.
6. The method according to claim 5, wherein the primary spring
elements are configured such that when the contact strip makes
contact with the contact wire, the primary spring elements are
deflected counter to the vertical direction, and the detecting step
comprises detecting the deflection of the primary spring
elements.
7. The method according to claim 2, which comprises arranging the
magnet element and the magnetic sensor element distributed on the
contact strip and on the carrier element and for detecting the
deflection of the contact strip relative to the carrier element,
determining the deflection of the primary spring element in
dependence on a magnetic field of the magnet element detected by
the magnetic sensor element.
8. The method according to claim 1, which comprises detecting, by
way of the sensor unit, an inclination of the contact strip
relative to the carrier element and/or dependent upon the
inclination of the contact strip and the deflection of the primary
spring element, a contacting point of the contact wire on the
contact strip.
9. The method according to claim 1, which comprises providing a
limiter element with end regions protruding laterally beyond the
contact strip and being supported by at least one secondary spring
element, and detecting the deflection of the contact strip and of
the limiter element relative to the carrier element.
10. The method according to claim 9, which comprises detecting a
deflection of the secondary spring element in and counter to the
vertical direction and/or an inclination of the contact strip
relative to the carrier element about an inclination axis extending
in the direction of travel.
11. The method according to claim 9, wherein the sensor unit
comprises a magnet element and a magnetic sensor element which are
displaceable relative to one another during the deflection, and the
method further comprises arranging the magnet element and the
magnetic sensor element distributed on the limiter element and on
the carrier element and for detecting the deflection and/or the
inclination, and determining the deflection of the secondary spring
element and/or the inclination of the contact strip relative to the
carrier element in dependence on a magnetic field of the magnet
element detected by the magnetic sensor element.
12. The method according to claim 1, which comprises determining a
contact force with which the contact wire contacts the contact
strip by way of the sensor unit, dependent upon the deflection.
13. A current collector of a vehicle for contacting a contact wire
of an overhead line that extends in a direction of travel, the
current collector comprising: a carrier element movably mounted for
movement in, and counter to, a vertical direction; a contact strip
for contacting the contact wire; at least one primary spring
element resiliently mounting said contact strip on said carrier
element, enabling said contact strip, on contacting the contact
wire, to be deflected out of a rest position relative to said
carrier element; and a sensor unit for detecting a deflection of
said contact strip relative to said carrier element, thus enabling
an evaluation, in dependence on the deflection, whether or not said
contact strip is in contact with the contact wire of the overhead
line.
14. The current collector according to claim 13, wherein said
sensor unit comprises a magnet element and a magnetic sensor
element.
15. The current collector according to claim 14, wherein said
magnetic sensor element is a magnetoresistive sensor element.
16. The current collector according to claim 14, wherein said
magnet element and said magnetic sensor element are arranged
distributed on said contact strip and on said carrier element.
17. The current collector according to claim 14, wherein said
magnet element and said magnetic sensor element are mounted for
movement away from one another when the deflection between said
contact strip and said carrier element decreases.
18. The current collector according to claim 13, which comprises a
limiter element on said contact strip and at least one secondary
spring element resiliently mounting said limiter element on said
contact strip.
19. The current collector according to claim 18, wherein said
sensor unit comprises a magnet element and a magnetic sensor
element, and wherein said magnet element and said magnetic sensor
element are arranged distributed on said limiter element and on
said carrier element.
20. The current collector according to claim 13, wherein at least
two sensor units are arranged for measuring the deflection and/or
an inclination at two mutually different sites.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a method for testing whether a current
collector is in contact with a contact wire, and a current
collector.
Nowadays, in the context of electrification in the automobile
sector, different types of electrical energy supply to electric
motor-driven vehicles are used. One of these types is, for example,
a supply to such a vehicle by means of an overhead line arranged
over a roadway, as is typically used with rail vehicles. For energy
supply, vehicles configured therefor, in particular, heavy goods
vehicles have a current collector which contacts the overhead line
and thereby ensures the energy supply.
Bringing the current collector into contact with the overhead line
is to be ensured not only from a functional standpoint, but from a
technical safety standpoint also, a functioning contacting of the
current collector with the overhead line is important.
SUMMARY OF THE INVENTION
Proceeding therefrom, it is an object of the invention to provide a
method with the aid of which, a bringing into contact of a current
collector with an overhead line can be easily detected, and to
provide a current collector which is configured to carry out the
method.
The object as far as the method is concerned is achieved, according
to the invention, by means of a method having the features as
claimed.
Advantageous embodiments, developments and variants are the subject
matter of the subclaims.
The method is configured for testing whether a current collector of
an electric motor-driven vehicle is in contact with a contact wire
of an overhead line extending in a direction of travel. The current
collector is configured, in particular, as a pantograph. The
contact wire is typically arranged above a roadway by means of a
plurality of suspension cables for electrical supply to the
electric motor-driven vehicle.
An electric motor-driven vehicle should be understood herein to be,
in general, a (passenger) motor vehicle and, in particular a heavy
goods vehicle and/or a bus, which has an electric motor as the
drive motor, either in the manner of a hybrid vehicle (combination
of combustion engine and electric motor) or in the manner of a
purely electric motor-driven vehicle. Preferably, the electric
motor-driven vehicle described is not rail-bound and is therefore
designed to travel on a, for example, asphalted roadway. For the
sake of simplicity, the electric motor-driven vehicle is denoted
hereinafter as a vehicle, for short.
The current collector is movable in a vertical direction and
counter thereto, i.e. in particular, upwardly and downwardly, and
comprises a carrier element. The carrier element is typically
designated a rocker or a rocker frame. Furthermore, the carrier
element is configured as a transverse strip, that is, oriented
transversely, in particular perpendicularly, to the contact wire.
In particular, the carrier element is also oriented perpendicularly
to the vertical direction.
Furthermore, the current collector comprises a contact strip
resiliently mounted on the carrier element by means of at least one
primary spring element, for example, a helical spring element. The
contact strip is preferably also configured as a transverse strip
oriented parallel to the carrier element, that is, transversely to
the direction of travel and serves for contact with the contact
wire. In other words: the contact strip taps off a (supply) voltage
that is typically applied to the contact wire. For this purpose,
the contact strip is moved toward the contact wire in the vertical
direction and, in particular, from below and, during travel, slides
along it. Preferably, the vehicle has two contact strips arranged
spaced apart, one behind the other.
In addition, the current collector has a sensor unit for detecting
the contacting of the current collector and, in particular, of the
contact strip with the contact wire. This means that the contact
strip, upon contacting the contact wire, is deflected out of a rest
position counter to the vertical direction relative to the carrier
element. Herein, the expression rest position should be understood
to mean specifically a position of the current collector, in
particular, a position of the contact strip relative to the carrier
element in which the contact strip is positioned force-free--with
the exception of gravity--for example, with the current collector
retracted. The deflection relates to the principle that during
contacting, the contact strip is pressed with a pressing force
"from below" against the contact wire. The pressing force is also
termed the contact force. However, the contact wire itself also
exerts a counterforce on the contact strip. In other words: due to
the arrangement by means of the suspension cables and the intrinsic
weight of the contact wire, the wire hardly yields in the vertical
direction when the contact strip is moved "from below" against the
contact wire. Thus the primary spring elements have a force applied
to them and the contact strips are deflected relative to the
carrier element. The deflection of the contact strip relative to
the carrier element corresponds to a distance between the contact
strip and the carrier element. The distance, i.e. the deflection,
is dependent, in particular, on the pressing force and the
corresponding counterforce. In particular, in the presence of a
greater pressing force, that is, a stronger pressing of the contact
strip against the contact wire, the deflection is reduced, i.e.
lessened. Conversely, with a corresponding unloading, the
deflection is increased.
This deflection is detected by means of the sensor unit and it is
subsequently determined whether the contact strip is contacted by
the contact wire. This takes place, for example, by means of a
comparison of the deflection with a deflection threshold value. The
"deflection threshold value" should be understood herein to mean
specifically a deflection beyond which, in particular, a functional
contacting of the contact strip with the contact wire has taken
place.
By means of the sensor unit, it is therefore detected whether and
preferably to what extent the deflection changes, i.e. whether and
preferably by how much the deflection lessens or increases. In
other words: the deflection is changed during the contacting, i.e.
increased or decreased, and the sensor unit detects the changed
deflection and preferably also quantifies it.
By this means, a detection of a functional contacting of the
contact strip to the contact wire and thus a functional electrical
supply to the vehicle is ensured. Furthermore, the testing of the
contacting is independent of an electrical state of the contact
wire. The electrical state should be understood herein to be an
operational state of the contact wire, i.e. whether the contact
wire has the (supply) voltage applied to it or not.
Preferably, the sensor unit has a magnet element and a magnetic
sensor element. The magnet element and the magnetic sensor element
are preferably displaceable or movable relative to one another
during the deflection.
In order to enable a simple detection of the deflection, according
to a suitable embodiment, a deflection of the primary spring
element in, or counter to, the vertical direction is detected. This
enables a simple detection of the contacting of the contact strip
by the contact wire.
Furthermore, an inclination of the contact strip relative to the
carrier element about an inclination axis extending in the
direction of travel is preferably detected. The advantage of this
embodiment is that alternatively or in addition to the detection of
the deflection of the primary spring element, a detection of an
inclination angle defined by the inclination of the contact strip
can also take place.
According to a suitable development, the contact strip is
resiliently arranged on the carrier element by means of two primary
spring elements spaced apart from one another. Preferably, a
primary spring element is arranged on each side (seen in the
direction of travel, to left and right) on the carrier element.
The advantage is that, in particular, the detection of the
inclination of the contact strip takes place more exactly than, for
example, in an embodiment with only one spring element. Preferably,
two sensor units are also provided thereby. In other words: in
order to detect the inclination of the contact strip, according to
the embodiment described, two deflections (one for each spring
element) are used. In a particularly preferred embodiment, a sensor
unit is arranged close to each of the primary spring elements.
Thereby, "close" should be understood, in particular, as meaning
that the sensor unit is arranged not more than 5 cm from the
associated primary spring element.
Preferably, the primary spring elements are configured such that
when the contact strip makes contact with the contact wire, said
spring elements are deflected counter to the vertical direction.
Hereby, the deflection of the primary spring elements is
detected.
Preferably, the magnet element and the magnetic sensor element are
provided for the detection of the deflection. The elements (magnet
element and magnetic sensor element) are preferably arranged, in
particular held, distributed on the contact strip and on the
carrier element. "Distributed" should be understood herein, in
particular, to mean that an element selected from a magnet element
and a magnetic sensor element is arranged on the contact strip and
the respective other element selected from a magnet element and a
magnetic sensor element is arranged on the carrier element.
Alternatively or additionally, a plurality of magnet elements and
magnetic sensor elements corresponding thereto are provided and
also arranged for detecting the deflection. By this means, the
detection is still further improved.
The magnet element, for example, a permanent magnet, emits a
magnetic field which can be, and also is, detected by the magnetic
sensor element. In a deflection of the contact strip relative to
the carrier element, that is, a deflection of the primary spring
element, the elements (magnet element and magnetic sensor element)
are also displaced, i.e. moved, relative to one another. It is
therefore made possible that the deflection is determined,
dependent upon a magnetic field of the magnet element detected by
the magnetic sensor element.
In a suitable embodiment, the magnetic sensor element is configured
as a sensor element on the basis of a magnetoresistive effect. In
the description of the concepts below, these are based upon such an
embodiment utilizing the magnetoresistive effect, but without any
loss of generality. The aforementioned concepts, however, are also
usable analogously for embodiments with sensor units of different
functional methods or design types, in particular, with other
magnetic sensor elements which utilize alternative or additional
other effects. In a suitable embodiment, the magnetic sensor
element is configured as a Hall effect sensor which detects a
voltage which is dependent, in particular, upon the magnetic field
of the magnet element and is applied to the magnetic sensor
element. As further alternatives, sensor units are used which
utilize a so-called anisotropic magnetoresistive effect (AMR) or a
giant magnetoresistance effect (GMR), whereby however, the
detection of the deflection and the design of the sensor unit can
differ from the concepts set out below.
The magnetic sensor element is designed, as mentioned above, for
detecting magnetic fields. For this purpose, the magnetic sensor
element preferably has at least two layers of a ferromagnetic
material which are separated by an intermediate layer of a
non-ferromagnetic material. In an arrangement of this type, the
magnetizations of the two layers of ferromagnetic material orient
themselves in opposing directions dependent upon a thickness of the
non-ferromagnetic intermediate layer. A magnetic field applied from
outside the arrangement at least partially reverses the orientation
into a different direction. From this is found the "sensitivity" of
the sensor unit to magnetic fields. By reason of the fact that an
electrical resistance of the arrangement correlates to the
orientation of the magnetization, therefore a magnetic field which
influences the magnetization is measurable by means of a change in
the value of the electrical resistance. Such a change in the
magnetization takes place, for example, when the magnetic sensor
element is exposed to a magnetic field.
In other words: by means of the deflection opposed to the vertical
direction, the magnetic sensor element which is arranged, for
example, on the carrier element, is exposed to the magnetic field
of the magnet element, by means of which the magnetization and thus
also the value of the electrical resistance of the magnetic sensor
element changes. For example, the value of the resistance rises
with increasing deflection. This value change of the electrical
resistance is subsequently detected, for example, by means of an
evaluating unit connected wire-bound to the magnetic sensor element
and it is determined whether the contact strip is in functional
contact with the contact wire. For this purpose, for example, a
resistance threshold value is stored in the evaluating unit, on
exceeding of which a functional contacting is detected, that is,
recognized.
The sensitivity of the magnetic sensor element to magnetic fields
is not restricted in the present case to a particular orientation
of the magnetic field. By this means, it is also made possible, for
example, to detect the inclination of the contact strip by means of
the magnetic sensor element in that only subregions of the magnetic
sensor element exposed to the magnetic field lead to a measurable
change of the electrical resistance of the magnetic sensor
element.
Consequently, according to a suitable embodiment, the inclination
of the contact strip relative to the carrier element is detected.
Furthermore, alternatively or additionally, dependent upon the
inclination of the contact strip and the deflection of the primary
spring element, a contacting point of the contact wire on the
contact strip is detected. "The contacting point" should be
understood herein specifically as a point "on" the contact strip
with which the contact strip makes contact with the contact wire
and thus slides thereon.
In other words: if the current collector, in particular the carrier
element, is viewed in the direction of travel, the primary spring
elements are preferably arranged at the end on the carrier element
and on the contact strip. In particular, by this means, during
operation the primary spring elements are arranged on both sides of
the contact wire. If the vehicle now moves, for example, to the
right (seen in the direction of travel), the contact wire is
displaced to the left on the contact strip. By this means, the left
primary spring element experiences a greater displacement than the
right primary spring element. "Deflection" should be understood
herein to be specifically a deflection of the left primary spring
element counter to the vertical direction, that is, a compression
of the left primary spring element, and specifically for the right
primary spring element, a deflection in the vertical direction,
that is, a stretching or extension.
The contact strip is thus inclined to the left by an inclination
angle about the rotary axis extending in the direction of travel.
Consequently, the magnetic sensor element and in particular a
left-hand region of the magnetic sensor element is, for example,
more strongly exposed to the magnetic field of the magnet element
than a right-hand region of the magnetic sensor element.
Alternatively, the contact strip is deflected so far to the left
that the right-hand region of the magnetic sensor element is not
permeated by the magnetic field at all. Making use of the
deflections of the two primary spring elements, in particular a
deflection resulting from the two deflections and a value of the
inclination angle resulting therefrom, a determination of the
contacting point (here, in a left-hand region of the contact strip)
is achieved. Furthermore, the changed value of the electrical
resistance is also taken into account.
For example, a particular deflection value (how far the primary
spring elements are each deflected or compressed) and/or a
resulting inclination angle in combination with an electrical
resistance value of the magnetic sensor element is assigned to each
possible contacting point.
According to a suitable development, by means of at least one
secondary spring element, for example, a helical spring element, a
limiter element is arranged on the contact strip, whereby a
deflection of the contact strip and of the limiter element relative
to the carrier element on contacting the contact strip with the
contact wire is detected. Preferably, the limiter element is
arranged by means of two secondary spring elements spaced apart
from one another on the contact strip. For this purpose, the
secondary spring elements are each arranged at an end side on the
limiter element and on the contact strip.
The limiter element also has end regions protruding laterally
beyond the contact strip. "End regions" should be understood herein
specifically to be ends of the limiter element oriented in the
vertical direction and, for example, bent over. In particular, by
means of the protruding end regions, a detection of a departure of
the contact wire from a permissible region is enabled. "The
permissible region" should be understood herein to be a region of
the contact strip with which the contact wire must be mechanically
in contact in order also to ensure an electrically operational
contact. Normally, the permissible region is a width of the contact
strip. The width of the contact strip should be understood
herein--seen in the direction of travel--to be a lateral extent (to
left and right) of the contact strip. As a result of the fact that
the contact wire "operates" within the permissible region, the
permissible region is typically also designated an operating region
and consequently the limiter element is also designated an
operating region limiter.
Preferably, the deflection of the contact strip and thus also of
the limiter element relative to the carrier element in the form of
a deflection of the secondary spring element in and counter to the
vertical direction is detected. Furthermore, an inclination of the
contact strip and thus also of the limiter element relative to the
carrier element about an inclination axis is detected. The
inclination axis extends preferably in the direction of travel.
The advantage is that, due to the additional arrangement of the
limiter element, the detection of the deflection and the
inclination for detecting the contacting of the contact strip with
the contact wire and for detecting the contacting point is not
influenced.
According to a preferred embodiment, for detecting the deflection
and/or the inclination, the magnet element and the magnetic sensor
element are provided. According to this embodiment, the elements
(magnet element and magnetic sensor element) are arranged
distributed on the limiter element and the carrier element.
"Distributed" should be understood herein, in particular, to mean
that an element selected from a magnet element and a magnetic
sensor element is arranged on the limiter element and the
respective other element selected from a magnet element and a
magnetic sensor element is arranged on the carrier element.
Consequently, the deflection of both the primary spring element and
also the secondary spring element as well as the inclination of the
contact strip about the inclination axis relative to the carrier
element is detected dependent upon the magnetic field of the magnet
element detected by the magnetic sensor element.
In addition, a departure of the contact wire from the permissible
region from the contact strip and a departure of the contact strip
by the contact wire is detected. This will now be described in
greater detail using an exemplary procedure:
If the vehicle now moves, for example, to the right (seen in the
direction of travel), the contact wire is displaced to the left
"on" the contact strip. If the vehicle now moves sufficiently far
to the right and consequently the contact wire moves sufficiently
far to the left that it "slips" off the contact strip, then the
contact wire impinges upon the limiter element which is arranged
with two secondary spring elements spaced apart from one another on
the contact strip. For this purpose, the limiter element is bent at
each end side as previously mentioned, for example, in the vertical
direction ("upwardly") such that each--upwardly--bent part of the
limiter element abuts the ends of the contact strip.
Through the impinging of the contact wire against the limiter
element, in particular on the (upwardly) bent left-hand part of the
limiter element, the limiter element is deflected. In the present
example, the limiter element is deflected counter to the vertical
direction such that it inclines to the left. Thus, for example, the
left-hand secondary spring element is deflected counter to the
vertical direction and the right-hand secondary spring element is
compressed in the vertical direction. A deflection of the primary
spring elements relative to the carrier element which results by
reason of the contacting of the contact strip by the contact wire
and the inclination angle of the contact strip are abruptly
changed, for example, on departure of the contact wire from the
contact strip. "Abruptly changed" should be understood herein to
mean specifically that, for example, if the contact wire departs
from the contact strip, the primary spring element rebounds counter
to its deflection caused by the contact wire. This "rebounding"
also acts on the limiter element arranged by means of the secondary
spring element on the contact strip. I.e. the magnet element
arranged, for example, on the limiter element also "co-springs",
whereby the "co-springing" manifests, for example, as a sudden
change of the electrical resistance of the magnetic sensor
element.
In other words: the magnetic sensor element "responds to" and
detects the exposure to the magnetic field of the magnet element.
When the contact wire departs from the contact strip and the
aforementioned springing movement of the contact strip and also of
the limiter element takes place, the magnetic sensor element is
permeated, for example, by a changing magnetic field. This changing
permeation (due to the springing motion, the magnetic field passes
into the magnetic sensor element and then out again) by the
magnetic field also changes the measured electrical resistance of
the magnetic sensor element in a sudden manner. Due to this sudden
variation of the measured resistance value, subsequently, a
departure of the contact wire from the contact strip can be
deduced.
Preferably, a contact force with which the contact wire contacts
the contact strip is determined by means of the sensor unit,
dependent upon the deflection. In particular hereby, the deflection
of the primary spring elements is used, since these directly
connect the carrier element mechanically to the contact strip that
is deflected relative to the carrier element.
In principle, a plurality of suitable possibilities exist for
arranging the magnet element and the magnetic sensor element. In a
first variant, the two elements are mounted such that they are
moved toward one another if the deflection between the contact
strip and the carrier element becomes reduced. Hereby, the
deflection then correlates to the contact force such that a smaller
deflection between the carrier element and the contact strip
corresponds to a greater contact force. In the present case, a
"smaller deflection" should be understood specifically as a
compression of the primary spring elements which are configured,
for example, as helical spring elements. In a second variant, the
two elements are mounted such that they are moved away from one
another if the deflection between the contact strip and the carrier
element becomes reduced. Hereby, the deflection then correlates to
the contact force such that a larger deflection between the carrier
element and the contact strip corresponds to a greater contact
force.
Particularly in relation to the above-mentioned second variant, the
current collector suitably comprises a holder which is mounted on
the contact strip or on the limiter element. The holder is fed
round the carrier element and grasps it such that the element
(magnetic sensor element or magnet element) fastened to the holder
is arranged, in particular, beneath the other element. As a result
thereof, on a reduction of the spacing between the contact strip
and the carrier element, a spacing between the magnet element and
the magnetic sensor element is increased.
It is advantageous that, by means of a sensor unit, two parameters,
for example, the contacting of the contact strips to the contact
wire and simultaneously, the contact force can be determined and
preferably also are determined. Furthermore, a complex sensor unit
which is configured, for example, for an optical force measurement
can be dispensed with.
The object as far as the current collector is concerned is
achieved, according to the invention, by means of a current
collector as claimed.
The current collector is configured such that it serves for
carrying out the method described above.
The advantages described in relation to the method and preferred
embodiments can be applied, mutatis mutandis, to the current
collector and vice versa.
The current collector is movable in and counter to a vertical
direction and is configured for an electrical supply of a
preferably not rail-bound, electric motor-driven vehicle. For this
purpose, the current collector makes contact with a contact wire of
an overhead line extending in a direction of travel. In particular,
the current collector is constructed in the manner of a
pantograph.
For this purpose, the current collector has a carrier element,
usually termed a rocker frame. The carrier element is configured,
in particular, as a transverse strip, that is, oriented
transversely, preferably perpendicularly to the contact wire.
Furthermore, the current collector comprises a contact strip,
resiliently arranged on the carrier element with at least one
primary spring element, for contacting the contact wire. The
contact strip is therefore deflectable out of the rest position
relative to the carrier element on contacting the contact wire.
Herein, "on contacting" should be understood to mean, firstly, a
contacting procedure in which the current collector moves in the
vertical direction to the contact wire and, secondly, a contacted
state of the current collector with the contact wire after said
movement toward it. In order to detect the deflection of the
contact strip relative to the carrier element, the current
collector has a sensor unit whereby, dependent upon the deflection,
an evaluation takes place of whether the contact strip is in
contact with the contact wire. Furthermore, the contact strip is
also configured as a transverse strip and is oriented transversely,
preferably perpendicularly, to the contact wire.
The evaluation takes place alternatively or additionally by means
of an evaluating unit which is arranged, for example, on a control
unit of the current collector or, for example, within the vehicle.
The evaluating unit is, hereby, preferably connected by means of a
wire-bound or wireless connection to the sensor unit, for example,
by means of an electrical line.
Preferably, the sensor unit has a magnet element and a magnetic
sensor element.
According to a preferred embodiment, the magnetic sensor element is
configured as a magnetoresistive sensor element, for example, as a
giant magnetoresistance sensor element (GMR sensor element). The
"magnetoresistive sensor element" should be understood in the
present case to mean specifically a sensor element which operates
on the basis of a magnetoresistive effect. In general,
"magnetoresistive effects" should be understood herein to be
effects which define a change of an electrical resistance of a
material by application of an external magnetic field.
Alternative embodiments of the sensor unit use another functional
method or have a different design, in particular, with other
magnetic sensor elements which utilize alternative or additional
other effects. For example, the magnetic sensor element is
configured as a Hall effect sensor which detects a voltage which is
dependent, in particular, upon the magnetic field of the magnet
element and is applied to the magnetic sensor element. Furthermore,
in particular, sensor units are used which utilize, in particular,
a so-called anisotropic magnetoresistive (AMR) effect or a giant
magnetoresistance (GMR) effect.
Suitably, the magnet element and the magnetic sensor element are
arranged distributed on the contact strip and on the carrier
element. For example, the magnetic sensor element is arranged on
the carrier element and the magnet element is arranged on the
contact strip. By this means, a simple detection of the deflection
is, for example, by means of an influencing of the electrical
resistance of the magnetic sensor element by the magnetic field
emitted by the magnet element, as set out above in the description
of the method.
According to a preferred development, a limiter element is arranged
resiliently mounted on the contact strip by means of at least one
secondary spring element, in particular, by means of two secondary
spring elements. The limiter element is arranged, in particular,
counter to the vertical direction, that is, beneath the contact
strip. The limiter element also preferably has end regions at each
end side oriented, for example bent, in the vertical direction
("upwardly"). I.e. the end regions extend--seen in the direction of
travel--along the lateral ends of the contact strip. Thus, a
departure of the contact wire from the contact strip is detectable
as described above.
Suitably, the magnet element and the magnetic sensor element are
arranged distributed on the limiter element and on the carrier
element in the manner already described.
According to an advantageous development, at least two sensor units
are provided for measuring the deflection and/or inclination at two
different sites. Particularly suitable is an embodiment in which
two primary spring elements are arranged and, in the region of each
primary spring element, i.e. for example not further than 20 cm or,
in particular, not further than 10 cm removed therefrom, a sensor
unit is provided, that is, in total two sensor units. In this way,
the inclination and/or the deflection can advantageously be
determined in an improved manner.
Exemplary embodiments of the invention are explained below in
greater detail, making reference to the drawings. Therein, in
partially greatly simplified representations:
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a schematic side view of an electric motor-driven
vehicle,
FIG. 2 is a sketched representation of a current collector
according to a first variant,
FIG. 3 is a sketched representation of the current collector
according to a second variant,
FIG. 4 is a sketched representation of the carrier element
according to the second variant in a deflected state, and
FIG. 5 is a side view of the current collector according to a third
variant.
In the drawings, details having the same function are each provided
with the same reference signs.
DESCRIPTION OF THE INVENTION
The vehicle 2 shown in FIG. 1 has a current collector 4 which, in
the exemplary embodiment is arranged on the roof of the vehicle 2.
The current collector 4 has a current collector arm 6 and a carrier
element 8 arranged at one end of the current collector arm 6. With
the other end, the current collector arm 6 is arranged on the roof
of the vehicle 2.
The current collector 4 is movable in and counter to a vertical
direction V and serves for electrical supply to the vehicle 2 with
an (operational) voltage. The voltage is typically provided by
means of an overhead line 10. The overhead line 10 extends in a
direction of travel F and is arranged above a roadway 12.
Furthermore, the overhead line 10 comprises a contact wire 14 and a
plurality of suspension cables 16 for arrangement above the roadway
12. The contact wire 14 typically has the (operational) voltage
applied to it.
For tapping off the (operational) voltage, the current collector 4
has contact strips 18 (see FIG. 2) arranged on the carrier element
8. The contact strips 18 are oriented transversely to the contact
wire 14 and for the supply of the vehicle 2 are moved in the
vertical direction V ("from below") to the contact wire 14. The
contact strips 18 thus slide along the contact wire 18 during
driving operation and ensure the electrical supply to the
vehicle.
In an alternative (not shown), a further sensor unit 22 is arranged
in the region of each of the primary spring elements 20. Herein,
the magnet elements 24 are each arranged not further removed than
10 cm from the site at which the associated primary spring element
20 is connected to the contact strip and the magnetic sensor
elements 26 are each arranged not further than 10 cm from the site
at which the associated primary spring element 20 is connected to
the carrier element 8.
FIG. 2 shows a sketched representation of a carrier element 8 seen
in the direction of travel F according to a first variant. The
contact strip 18 is arranged on the carrier element 8 by means of
two primary spring elements 20. In the exemplary embodiment, the
contact strip 18 is arranged in the vertical direction, that is,
above the carrier element 8. For this purpose, a primary spring
element 20 is arranged at each end on a side facing toward the
respective other element selected from the carrier element 8 and
the contact strip 18. Both the contact strip 18 and the carrier
element 8 are configured in the exemplary embodiment as transverse
strips and are thus oriented transversely to the contact wire
14.
By means of the primary spring elements 20, the contact strip 18 is
mounted resiliently in and counter to the vertical direction V.
Furthermore, the contact strip 18 has a spacing A from the carrier
element 8. In order to detect a deflection of the contact strip 18
on contacting by the contact wire 14, the current collector 4, in
particular, the carrier element 8 has a sensor unit 22. The sensor
unit 22 has a magnet element 24, for example, a permanent magnet
element and a magnetic sensor element 26, for example, a giant
magnetoresistance element.
In the exemplary embodiment, the magnet element 24 is arranged
centrally on the contact strip 18 and emits a permanent magnetic
field M. In the exemplary embodiment, the magnetic sensor element
26 is arranged on the carrier element 8 and is configured for
detection of the magnetic field M.
When the current collector 4, in particular, the contact strip 18
moves toward the contact wire 14, the contact strip 18 is "pressed"
against the contact wire 14. The contact strip 18 and thus also the
primary spring element 20 are deflected relative to the carrier
element 8, in particular, counter to the vertical direction V.
Thus, the spacing A is reduced. As a result thereof, a position of
the magnet element 24 relative to the magnetic sensor element 26
changes, whereby the magnetic sensor element 26 detects a magnetic
field change. For example, the magnetic field strength of the
magnetic field M increases as the spacing A decreases. Thus, on a
deflection by means of a contacting of the contact strip 18 by the
contact wire 14, the magnetic sensor element 26 is subjected to a
stronger magnetic field M than, for example, in a rest position.
"Rest position" should be understood herein to be a position of the
current collector 4 and, in particular, of the contact strip 18 in
which the contact strip 18 is, for example, not in contact with the
contact wire 14. The stronger magnetic field M has the consequence,
for example, within the magnetic sensor element 26 of an increase
in the electrical resistance of the magnetic sensor element 26,
whereby such a change is detectable.
For example, stored in an evaluating unit (not shown here) is a
threshold value of the electrical resistance, on exceeding of which
a functional contacting of the contact strip 18 with the contact
wire 14 takes place.
In addition, the arrangement described also detects an inclination
of the contact strip 18 by an inclination angle .alpha.. For this
purpose, dependent upon a displacement of the contact wire 14 in or
counter to a lateral direction S, a deflection of the--seen in the
direction of travel F--left-hand primary spring element 20 and of
the right-hand primary spring element 20 is determined. A different
deflection of the two primary spring elements 20, for example, due
to a non-central contacting of the contact strip 18--seen in the
direction of travel F--with the contact wire 14 is decisive for a
value of the inclination angle .alpha.. In other words: if--as seen
in the direction of travel F--a right-hand region of the contact
strip 18 makes contact with the contact wire 14, then the
right-hand primary spring element 20 is more strongly deflected
counter to the vertical direction than the left-hand primary spring
element 20. The contact strip 18 therefore inclines "to the right"
which, in the exemplary embodiment, has the consequence of
increasing the inclination angle .alpha. and an inclination of the
magnet element 24. At the same time, due to the inclination, an
orientation of the magnetic field M which permeates the magnetic
sensor element 26 changes. In the example described, a right-hand
region of the magnetic sensor element is now more strongly
permeated by the magnetic field M than a left-hand region
(described more exactly in relation to FIG. 4). This unequal
magnetic field permeation has the effect, again, of a detectable
change in the electrical resistance of the magnetic sensor element
26.
In addition, as a result of a combination of the deflection of the
primary spring elements 20 and the inclination angle .alpha., a
contacting point 28 of the contact wire 14 "on" the contact strip
18 can be deduced. For this purpose, for example, the different
deflections of the primary spring elements 20 are summed into a
resultant deflection and, on the basis of the detected parameters
(inclination angle .alpha. and resulting deflection), the
contacting point 28 can be deduced.
Dependent upon a deflection of the primary spring elements 20 and a
spring constant of the primary spring elements 20, a contact force
with which the contact strip 18 makes contact with the contact wire
14, that is, with which the contract strip 18 presses "against" the
contact wire 14, is also determined.
FIG. 3 shows the carrier element 8 according to a second variant.
In FIG. 3, the carrier element 8 has all the elements and units 18,
20, 22, 24, 26, as described in relation to the first
embodiment.
In addition, however, a limiter element 32 is arranged on the
contact strip 18 by means of a number of secondary spring elements
30, in the exemplary embodiment, two. The limiter element 32 is
arranged counter to the vertical direction, that is, on an
underside 34 of the contact strip 18. By means of the secondary
spring elements 30, the limiter element 32 is also mounted
resiliently in and counter to the vertical direction V and is
therefore deflectable relative to the carrier element 8 and the
contact strip 8.
On each end side, the limiter element 32 has end regions 36 which
are, for example, bent, oriented in the vertical direction V, that
is upwardly. The end regions 36 thus surround (due to the
arrangement of the limiter element 32 "underneath" the contact
strip 18) the contact strip 18. In other words: due to the fact
that the end regions 36 are upwardly oriented, they "protrude"
laterally past the ends of the contact strip 18.
Furthermore, according to the second variant, the magnet element 24
is arranged on the limiter element 32. Due to the arrangement of
the limiter element 32 on the contact strip 18, whereby the limiter
element 32 is therefore also deflected relative to the carrier
element 8 on contacting of the contact wire 14 on the contact strip
18, a determination of the contacting of the contact strip 18 with
the contact wire 14 is ensured similarly to the first variant.
Underlying the second variant is the concept that in addition, a
departure of the contact wire 14 from the contact strip 18 can be
detected. "Departure" should be understood herein particularly as a
lateral "sliding down" of the contact wire 14 from the contact
strip 18.
The detection of the departure will be described in greater detail
with an example by reference to FIG. 4.
FIG. 4 shows the carrier element 8 of the current collector 4 and
the contact strip 18, whereby the contact strip 18 is laterally
deflected, as seen in the direction of travel F. As already
described by reference to FIG. 3, in the following, the method for
detecting the departure of the contact wire 14 from the contact
strip 18 will be described in greater detail:
If, for example, the vehicle 2 now moves during driving operation
(and thus with a contacted connection of the contact strip with the
contact wire 14), to the left, as seen in the direction of travel,
the contact wire 14 is displaced to the right on the contact strip
18. If the vehicle 2 does not end the displacement to the left, the
contact wire 14 leaves the contact strip 18 in a right-hand
region.
Due to the fact that the end regions 36 of the limiter element 32
protrude past the ends of the contact strip 18, the contact wire 14
"presses" against the relevant end region 36, in the exemplary
embodiment, the right-hand end region 36. This results in a
deflection of the limiter element 32 relative to the carrier
element 8. In the exemplary embodiment, the right-hand secondary
spring element 30 is deflected counter to the vertical direction V
and the limiter element 32 inclines, forming the inclination angle
.alpha., to the right. Due to the fact that the magnet element 24
is arranged on the limiter element 32, this inclines similarly and
thus also permeates the magnetic sensor element 26 arranged on the
carrier element 8, as previously described, with an "inclined"
magnetic field M.
Since both the departure of the contact strip 18 and also a
(usually uncritical) displacement of the contact wire 14 on the
contact strip 18 causes a deflection of the magnet element 24 and
thus an inclined magnetic field M, the departure of the contact
strip 18 is to be distinguished from the displacement of the
contact wire 14.
For this purpose, for example, a variation of the resistance change
of the magnetic sensor element resulting from the magnetic field
permeation is tracked. This consideration is based thereon that, on
a departure of the contact wire 14 from the contact strip 18, as
compared with a simple displacement of the contact wire 14, as
previously mentioned, a jump is detectable in the variation of the
resistance value. Thus, for example, on determining such a jump in
the signal variation of the magnetic sensor element, a departure of
the contact wire 14 from the contact strip 18 is unambiguously
detectable by the aforementioned evaluating unit.
FIG. 5 shows a further variant of the current collector 4 as viewed
along the carrier element 8. Herein, a spacing between the magnet
element 24 and the magnetic sensor element 26 in the rest state I
along the vertical direction V is a minimum. The magnetic sensor
element 26 is herein arranged on the side of the carrier element 8
facing away from the contact strip 18, in other words, facing the
vehicle 2. In addition, a holder 38 which surrounds the carrier
element 8 is arranged on the contact strip 18, so that the magnet
element 24 fastened to the holder 38 is arranged spaced from the
magnetic sensor element 26 vertically in the direction of the
vehicle 2. Thus, on a reduction of the spacing A between the
contact strip 18 and the carrier element 8, the spacing between the
magnet element 24 and the magnetic sensor element 26 is
increased.
In an alternative (not shown in detail) and otherwise identically
constructed variant, the magnetic sensor element 26 is fastened to
the holder 38 and the magnet element 24 is fastened to the carrier
element 8.
Furthermore, in a further alternative embodiment (not shown) of the
current collector 4 according to FIG. 3, the limiter element 32
comprises the holder 38 surrounding the carrier element 8.
* * * * *